David Haye refused to blame an Achilles injury for his surprise loss to Tony Bellew at the O2 Arena in London.
The 36-year-old sustained the injury in the sixth round and was clearly struggling for the rest of the fight, before Bellew delivered an 11th-round stoppage that saw Haye fall through the ropes and his trainer Shane McGuigan throw in the towel.
"Tony is a great fighter -- that's what went wrong," Haye told Sky Sports.
"I trained great, I felt good going into this fight. I wanted to do a demolition, job but this guy has got the heart of a lion.
"I did not expect him to have the chin and durability he has. You took my best shots and got back up and put me down."
Haye, who went straight from the ring to the hospital to have his injury assessed, is already entertaining the idea of a rematch, if Bellew is willing to oblige.
He added: "I'd love to do it again. I loved it, the fans loved it. I've never been in a fight like that before. He beat me now fair and square.
"I can't think about world honours; I need to get past this guy. I'm at his mercy; there is no rematch clause. That's the best fight I have ever had."